1. Field of the Invention
This invention is related to non-dissipative snubber circuit apparatus and more particular to non-dissipative snubber circuit apparatus for dual-switch transformer-coupled switching regulators.
2. Description of the Prior Art
Protection of transistor power switches in switching regulators by a current snubber circuit is well known in the art; see, for example, "Designing Non-Dissipative Current Snubbers For Switched Mode Converters", E. C. Whitcomb, Proceedings of POWERCON.RTM. 6, May 2-4, 1979, 1st Printing April 1979 (pre-conference edition), pp B1-1 to B1-6; "Base Drive Considerations in High Power Switching Transistors", D. Roark, TRW.RTM. Power Semiconductors Application Note, No. 120(1/75), pp 1 to 11; and "Schottky Rectifiers Shine in Low-Voltage Switchers", R. Patel, Electronic Design, Dec. 10, 1981, pp 149 to 154.
More particularly, snubber circuits, or snubbers as they are sometimes simply referred to in the art, have found general acceptance in protecting switching regulators that use only a single transistor power switch, or a pair of transistor power switches that operate in a push pull mode, i.e. alternately or out of phase. These include snubbers of both the well known dissipative and non-dissipative types.
However, heretofore, in the prior art of which I am aware, for dual-switch transformer-coupled switching regulators wherein two in phase transistor switches are in series coupled relationship with the switching transformer, only dissipative snubber types have been used. Heretofore, a non-dissipative type has not been used with these last mentioned kind of switching regulators, herein sometimes referred to as a dual switch switching regulator, because in general of the circuit complexity required for implementation and the resultant problems associated with operating the two transistors in phase.